SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3ea3264401f6cd899129bbbc8d5027d8a0be0cb5ae598619f1daf159fb4b634' 
  AND token = 'WgipUgixBgWo4n5ZJRZs71JBqu+I7YeDTPg2QbmGUUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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