SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e2d181756e0b1eee2c0558d32b6a485b29d9573661d82f6b73ab4876da59482' 
  AND token = 'yK178UQwVgMj/WgfYHneYDXuQyk/Vmx/QPYeyVPzQlc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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