SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '990e6bfa4226ba463a12ea8feb4531f9d6bba90bd8ff606065bf1d8a60566c75' 
  AND token = 'ScVqvms/pzu9HY9Zf3p4BRm2YO24IlzVxn/ClHPr9BY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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