SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9de2babb5282c6338719dc413c38a7968ccd3f8dd13b691954effbbcc3bc2bee' 
  AND token = 'EUmgGUfq0MORDQzQMuH7uO+MgN5MZQzdBPrIeFVUVxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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