SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e588316c2309fe5d96a52ee10784654d2f32da357f378a80cb2c4f8b8fe8cf9' 
  AND token = '2lLj+HuuBbh9P2YxH/Ez36I/vO+KncZe0w2qWMTb61s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}