SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78256573f589c5222602367fed82bcde5faeca11c56f0ca4039d675d52f57d6b' 
  AND token = 'b/jG1U9kgLQ3rcX+qWfbz7QB8akIxV6sQ0O7xBO9i4o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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