SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91c171c73ddbc66c2840aa1565a31776055e1daf139ee9673e5f01fbc056d823' 
  AND token = 'w3jlav2u4aRwT5PPrgJvxsh4RRLY50E3Wd09UisOvvI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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