SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7842c862d43fea914b1b586ade097501a527c605ca9cdfeff46826af81d134bc' 
  AND token = 'FQsMNK/OF5mPZhAdPVQf8o5qqI7l/xmVD/7E2foj1xg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}