SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed652deb8729ffccf44d36cb22ca5c98c4a102ecbf7a2d6f94a246d3b6d3b715' 
  AND token = 'SX9/xKCtaDy4ZqupYi+0P0mBdObZv2/9V+9YcJ/DvLY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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