SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2f9fd04a72656fb185c4dd42380207cd71593a631ae23f69e48b0905c6058d0' 
  AND token = 'A/DRjuaEuszfmkLJspB+WGAe3H//FrfumnjMezshEKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00067

JSON explain

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