SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '039f5d4855ee836913698f10d20fabe8b5c4bdd147ecc3721e903829b74faf82' 
  AND token = 'BgEfGxkP46WCLvDDRqpO97gh9nph0SSuLSaIqXAg3Iw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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