SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ad6dc87cd9200aa56daff2713889ef4be855e78b780aee2b0ffe9169d03c2f0' 
  AND token = '/yuFzKzpaqjg/GZxcJaGp1g7iMJ2Uf0cPVVgUflFzjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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