SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f9666b172d64bcb919d89738332808b6833736d0abab577dc4fdfba963766e5' 
  AND token = 'YB2DJbpF276amA6cssp/Ee67DYMPy7Pb2oG/cvmqLfQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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