SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9be866fed83a52e1393633187b28315d49c145200af31daf72bdc501809eae43' 
  AND token = 'OxB4HgHliltuUjc4XWoB/Vz1oxXPWSfUAT1gy1/ygFw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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