SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a0ef2df7c1337d052189250706af050bef1f8bcb816d1621a68e7213949af60' 
  AND token = '3KGGxO2bN2soLAnypC1BtofksQLp/dvELX0DV15puDE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00099

JSON explain

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