SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5738c8c8b06fd11b3eed3dc5f402332d22fcb28da43c9a2bfc263fab9fc9bfd3' 
  AND token = 'i6mNpK3Fd9lg5BAYxDqITzfzEhuQfwa/L5vGuZ9QbGI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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