SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f745ee681b578d4969f230828d81b2a633c396956123a666bdc9adeaff32c9cc' 
  AND token = 'mstX0vzNT34KLqhzrpqCVekKlb9KOqAnLZbZTBMBKY8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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