SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f076bd227e26d322f31d0410d1f99f23ccfd3f48d49bb826de8b376e38f83715' 
  AND token = 'rPH1hYhOnIR7tNjLo6Vz5l/zCrOdiM1x9wB65V+rZuY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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