SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '549827387d794061e351c72db55fbf5f14d4381851c45085e194387a9c3260ca' 
  AND token = 'qkH2Q2OLF9pYxIW3YN8gjWrWPyFWi8BSC2rWID333Xc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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