SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f251eed11c809d6faf76a80e775a496f43221e595ab160a2bd7c70d56315bf83' 
  AND token = 's9KQvUTvOuo8s/fQ4JGqB/Ppos5zAIhG2CVuR3x/qK0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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