SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2fbfb89825111f52e00d69bce02c8b275a408509cde73d6cd54eb954ea5e2f4' 
  AND token = '8noMzknJsvMskJJVooNQ4BG7Bc3PJG5POnpv1VTxbsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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