SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f88ce255e7b8f58ba7b3e323f84d925539e376c7c20777e551b00d74e66fd78' 
  AND token = 'yq1IKuwHMLMoJHhxKimlGVp1uWJDGHRDBEHMNC2S4Iw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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