SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d22a6a123f863132e587adec46e46fae09e26112b673413f91f918b1e286d9c' 
  AND token = 'Y6kEHcGQeBpgYCMy27c6HJ/XHCgsKD+89vRSbSysJRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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