SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b3afff3f93aa845fd2c073498e20440fc3733a1daafaa4b4e117f4532b3b698d' 
  AND token = 'UNEpfflvrPuvrxRHPdUiZ5RWgZBB8HQBzKsHm7GC7VM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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