SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9614eb644783888410ed51798b15445c5d631543e6ac016f9ad7611296202a8' 
  AND token = 'Jc3ZVOGEV32Ls+s5Z5q8+pvA1veRhAtvjyEOdCgznwM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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