SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0a9c705afeb0dbc440c3487922bf9ac43c4c049c6be7ab5e920839dba62964e' 
  AND token = 'QujLqNjnfxYd6T1grBQljYFqb3Hgp3DOz7rmCfnEj38=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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