SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b99f0ab98ae06b0c96b5e18feab5ad79e25f29b3b2331098722ec69dd7a0d66' 
  AND token = 'UW71x/WTMXvfga1GF8mnNu5fVCriP05p+G8yYxPQ4Lg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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