SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7913bd17a8bdb31ce87242a3382700656f36f4d4987067be1adee61a68abf49' 
  AND token = '+IPpgKrJIbFqje91cni6iCXJjRbsAXTMOowGti2J6q8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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