SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e1de7caf4308483436c6a1215c3443a82d3dd782a2e422b4767935690169b45a' 
  AND token = 'cP8DMEiN1ZE1h8lVWMgH4Wjw5lWlM62ZWW6QSrfPfMM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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