SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '448267ff3d8951958d1b9f766d1c956e4131ae07863a90b18c99e3d484e51c0b' 
  AND token = 'xVt2q6gNXAiLPjnKTvBESW0mZ7CY4TCVu6GFdJUqW48=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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