SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce8d254f8cc1fe325f68efc393fe32f33f832feccf94f7d7a1b24549a0b9df31' 
  AND token = 'm4+k1gZYkElh5HGTU22sS3ZbISPbwgoXvUrRgAOYauM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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