SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8957cab820bd1c5aff3de23ec339d5101b357ed43515e01961fee3f22beb29da' 
  AND token = 'nZ3bARZUP0/Tvmtwb/HlkQJHUep5UOhGYdcrgHEVas4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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