SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68e1a9b3ba2b125d5ad9b298e4fbe4bf217a66168eaf4e5453ea0671e191f076' 
  AND token = '7VBNLatDy+jF8IF9rsue58KpJNPBzZy5nRR6bhBd6KA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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