SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6134e7956a62bc17873fe482af787dd00e2454247a67b6312ad398cb823fd8b0' 
  AND token = 'CyH4I/nRRYDbtWHaR3YoEnF+5XKN6z84aRafeenQjJ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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