SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9761bc988b2b7bb8386e155ddd62f73be0a1ebf8db70bcd0cd72f27aea0ac83f' 
  AND token = 'NOmvof+8Wyywfz4t2oSZ4qGFfm61jurvpkHiN/K85as=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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