SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1121221d26357ca1e896b982c90ae9044020030334495ac12cd5d82bd6c50dd' 
  AND token = '3trdhlKslhmVHTsxpbFS3WcdntdpVqmgzMe7HXufhKo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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