SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '6266db859bd087061e292a608674ca3a8cf2b3dea137ce0207fd5843ead37ba4' 
  AND token = 'FbdVx4ud69ajYNGnMZvz6bV94VnFFkEPqv1Qv9loxd0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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