SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd869f638c441a96c5a9b2cb6953dcf5a2864bb5e51dd1249f48146908218418b' 
  AND token = 'uvSHloyR0y4bnwo8lq71dlHGojHLPZCPkA+xfW3Rces=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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