SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '536053afd441ed2d7226b5322956f28666d44ef04f2050d1357c1bfca3ccf4fe' 
  AND token = 'cU8EMP82NRXrPlAj74LVGbunpClCa/gXrUkVk66jxPU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}