SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc20885acecf27667319716a67645b1cd52c2673fa2ff9d4a647d494135e0a8c' 
  AND token = 'r0JFuAxDKOZIhwom/rQ7jIw00ZcNWB9Ovm2SC3YNvYA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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