SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e80301e84371e722132e312e667eeff6895026d4984989bf96af2de406f8bc1' 
  AND token = 'J7uCGp5K2CkAwr8aDppYhUnOBD5Sh//pVqlKmQZQvmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}