SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59e36bbdffaa4a3ef98a1b22e651876ad316c192c7bcdad5c8f446adb60502dc' 
  AND token = 'tP8dq6Tsy2BPWjmnWTaFxHs1Qy9SZGV/Tr2C3B9P+W0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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