SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd4eb51527393db4ed51b5587988a2113fa5e0ff35865a99a6419df94799e1e9' 
  AND token = '+1lEcgXsJ/uUKpfHLzRIKqIopTGTVfMwdlnViACC/Ks=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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