SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce8dc7e0991c9303afa5cd15ef3592519c0d319a6af54cfdeb80da40393cca80' 
  AND token = 'dpdFrbqBsFclTLVemhPD94kQ3Quz7LLnRTN+sZBJBUw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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