SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2df55bdb6e7ccd718bd215c642106fec158b986d6c2a0e6ee18146bd0b9cd21' 
  AND token = 'IFj4ktZzrF4H99xJVfRQv0zjhjWWswW5EWk6BMDYB2Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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