SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de31a6e92325a6833c4cb7eea5225cf6f922df128261ec9352abf3b44bcd56cf' 
  AND token = '3MCrF3cLjF56kuEfJcN/M26JdvD5uVWTx7V8J54Ls3M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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