SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b665d6d6ceb58508b911a6a5470f96f8e47b87698a3ef3e91ae37c2fc72bac02' 
  AND token = 'KFm5TvXjxnZTnnmfsy+UD33Wwyhqih40/Ak81q1/fgo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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