SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e5527ea7ed15fd0fc0016dcb85992f971c8071481b802e84e08343eaf908ae0' 
  AND token = 'eqMNm0R5CI0mAxiCFCzBHZW6tmDvlnmsM6axpF56ezE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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