SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bf961ac834e813116ba2a4e4364b852bd4fe0152bd43b40d0867f49e8933549' 
  AND token = 'hEa57T66GJdUf0Z9aDrpDSG1akR9OxPWtqetsHCLFEc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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