SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a6a0c1e712d71eff953860431b1e736f52bbc330c5f1db2f4de39e5ccb20d7f' 
  AND token = 'lJIBpb+rjx9/Yf3qYr28z8vSkiFz9VzzgnUBHIqUxAE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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