SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '636a803b5cac9d9aeea1d22d1787f0213b8496ca144474bc527e5dbb5dab9e48' 
  AND token = '1KBLbSRndHfwqBUGPEM+udppksYSQbRBL0MLrG1PSo0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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