SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7a74a1ccd0e284307d9de31fd01f08a02b778bab97434b3cc8b0471d284178e' 
  AND token = 'kTL+Cipp0lHJ8Ztw3ArT+02pXkEI6O+nlkZeNNO2PGk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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