SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8543d19feb7d9cf9f86df2283c5f83a74fccb84aef7cfa54b471aa69c4df9fcc' 
  AND token = 'R1nqnCNntvNWzd/rOAXEj6phAKVuNE4wbsKMzAwSqG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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