SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9eba2c74e0fad81a969dabfcd24f551f2cd8888323dc77fc711080f7454d7c0' 
  AND token = 'VLHMB1aLPeXzbVYNMUry6wxOsNaHd+MLGul4FklaaQo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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