SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fb6028ba956623311aa057bce8116744c1c1ce11c7039e570b8ab3f51f2a295' 
  AND token = 'rLTKhG5VJJ98LUPZVqU/YsC3Chf0FzyNc3H+rmHXDEk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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