SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2804873ea7ca8af932f1d3e13a900a45005053d2521572459ce278b75c78c76a' 
  AND token = 'P39APMfDSDFWQokTJaN+mZohplFAITFq9BlsVASQjWs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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