SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74fca38ef745af32539cf3a8876fb71fe1b0576c0d89b8db6ba524a62023108e' 
  AND token = 'EiWTMvPkoHD61jWjcFctoOLaXJETho0gI7166xEXEqg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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