SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fb34437337ed1d6c4656040c0a414d118000f2f9425adec036c7be418a93ba6' 
  AND token = 'b/BcBr2sYwsMLiqLH2dztE38gANTQ1aOl566VY9rZMk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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