SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e84f73d33bb514b1f3080fe85e40aff102028c0c1d6645f3e2bfd65d056f495' 
  AND token = 'VRdd2ki6/fpXzUFefrxGBisjmOoPNZFMzP5PfIdL1Lo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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