SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19a830e4074a051ecae04a2f3708554886280ec0546b1a13fa9b9289bd7255ea' 
  AND token = 'rMFy4o//VGOqVWKHm3djm+3Z0TRsLKGwoZfpW45XjRc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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