SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42ff238cefc80dffc96b59ca6e69c5d7935019ad15af42be6a1784eb673807ab' 
  AND token = '7bPluDMdOyKwVEIrTZUqyoK+yTlGUM+Jtg6ZEcvV/78=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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