SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '899edc6a93a530cb4629b9fa11232da3c8c6e5d7edfcfbb9285966d3de8d4b92' 
  AND token = 'g7VDU+uKKdGca8cOpsR8pbcdzq/ryBJCMPR0iTnZsr8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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