SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b120437b4ba37701ea84fed1a06b367c386d18dd26a8b6a747c6208237fe5434' 
  AND token = 'HVclYWfsUG6gh+rClVZvfuowTqt+YcA8HOXGPOAkB6w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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