SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43672e619cadc43caabeb23b422629c4008074782eee1a9b83cd28e839136371' 
  AND token = 'reuingtkEh5S2AtuyUr7UPCeEmjsMcQkE1QZV137ffc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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