SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'c17fb8921f9b2bc4778c2e5402f7fd886b636929cd9becda8ceaf4062a46b511' 
  AND token = 'qao2yd2NeOJdA8kRWOk13jie3A3uDj2u5Ki6IecZUHk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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