SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'baf833c5f7704160fd184f99d129977fc0b55a57851c86b0db1685f77a950281' 
  AND token = 'gSxH6EyTV0DGrpsKupYUCOkt5O4+7NfzTeIIalkDOgM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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