SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3d680a013b07049ca343b124ea294b8e9758b02a3a5760c02a314d653f7f589f' 
  AND token = 'FgikzEFbKXn77JnB+NEGB/7jHpFIsN44Ms5BOKLnxLI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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